An FM multiplex broadcasting system is a broadcasting system in which an audio signal and additional information are multiplexed and broadcasted. The additional information may preferably include, for example, a broadcasting station's name and time data. Depending on the additional information, a listener of the FM multiplex broadcast may use the additional information.
A variety of FM multiplex broadcasting systems have been developed in the United States, Europe and Japan. For example, such systems include Subsidiary Communication Authorization (SCA) in the U.S. and Radio Data System (RDS) in Europe.
The RDS system uses, for example, a program service name (PS) which identifies the names of broadcasting stations, a music/speech switch (M/S) which identifies whether a broadcast program is music or speech and a clock time (CT), as the additional information.
Further, it is preferable to broadcast an audio signal of, for example, a music piece, with character data associated with the music piece. The character data may include, for example, the name of the music piece, the title of an album which includes the music piece and the names of artists who play the music.
As a result, a listener of the program can visually confirm the character data displayed on the display of a receiver. For example, a listener can confirm the name of the music piece, the title of an album which includes the music and the names of the artists who play the music.
However, it is necessary to prepare the character data and to associate the character data with the audio signal, before the audio signal and the character data associated with the audio signal are broadcast. In other words, it is necessary to make a database of character data. It is expensive to make and to maintain such a database.